The one job that we did in recent memory that was in -355F cryogenic service (liquid o2 one side, liquid n2 other side) had full x-ray but I believe it was a customer requirement and not a code requirement.
We also definitely performed hydrotest and not pneumatic test. Most companies that...
I assumed by the same condenser, you mean that the length of the condenser is the same. If the length of the condenser is half, then the pressure drop is an additional 1/2, which makes 1/8.
The words circuit, feeds, and same condenser, is not typical lingo for what you are asking.
You will get about 1/4 the pressure drop. You had the correct methodology in your original post.
1/2 the flowrate will lead to 1/2 the velocity which will lead to about 1/4 the pressure drop, since it is a function of v^2.
Hope this helps.
I am not the original poster and the drawing is just used to make sure I understand what the OP was talking about. I simplified my drawing by making it 1 pass, but it would work with multiple passes as well. I think the goal of the OP is just to get a rule of thumb or understanding of the...
To be more clear, I assumed this flow diagram. Pardon my handwriting and shorthand.http://files.engineering.com/getfile.aspx?folder=a5027b43-abcb-45f7-9ae6-9499ae913479&file=20170519091655140.pdf
Paul,
If I am following you correctly, which I think I am, roughly 8 times is correct as a rule of thumb.
For the record, I am assuming that the double circuit design is two units in parallel, and each unit is half the length but same tube count as the full circuit (1 unit).
I was advised by my AI that under the rules of UG-15(a), we are allowed to qualify SA-387 9Cr based on the values of a different product form of 9Cr (ex. SA-213 T9 tubing). Therefore, we would be able to use SA-387 9Cr for this exchanger.
My customer has allowed me to use Grade 91 Chrome for...
So my understanding is that SA-387 Grade 9, which is readily used in refineries for pressure vessel materials in high temp application, is wrongfully used?
Grade 91 is a different material with a different P-no. It is not really interchangeable.
I have contacted my inspection agency for their...
Hi Guys,
I am designing a unit to ASME Section VIII-1 that is 9 Cr-Mo. I found all the other forms in Section II-D but the stress values are not there for plate. I checked in Section II-A under SA-387 and I did find grade 9 so it is an approved material.
Any thoughts or ideas how I am to...
Thanks. I had a similar chart that I was interpolating based on but I was wondering if I could get a little more precise since the numbers are logarithmic at these pressures.
We are doing a vacuum dry for a customer to -20C and we reached a pressure of 0.576 torr (below target of 0.782 torr). Great. They are asking what does this translate to in temperature. Obviously, this is below -20C but how do I calculate the actual value. Is there a simple calculation to get a...
It is bolting to an existing tubesheet. The original design had a different material of construction that led to a much thinner floating head. They changed the material to titanium which is leading to the dished head being way too thick to get formed.
Thanks for the response marty. I tried doing that but unfortunately, compress doesn't let me just do a blind flange. It needs to be bolted to an appendix 2 flange. The appendix 2 flanges that I have tried do not have enough bolting to pass, whereas a dished cover has enough bolting. This is...
Just to clarify, I mean a box design such as the attached.http://files.engineering.com/getfile.aspx?folder=7c2086c3-ef6d-4214-b099-e2ae04f8e2a3&file=37-E-14_Hogout.pdf
I am trying to design a dished cover in compress out of a hogged out forging. Does anyone have a suggestion as to best model this configuration, since there is no strict hog out option in compress.
Please advise,
Compress does calculate the stress ratio. Make the sure the "calculate the mawp" is active. Also, make sure the thickness of the component is enough to lower the stress below the 0.35.
Mech2325, I did notice the same thing. I was waiting for someone to find a fix on the Compress Forum section, when you posted their originally. I could not find one. It is very odd that this was overseen by Codeware.
Compress does calculate weight corroded, uncorroded, the hydrotest case and any operating case you want to run with any liquid level and specific gravity. The saddles can be checked in any number of cases. I am very interested as to why it only performs the base shear in the dry corroded state.
Helium Leak Test is commonly done to check tube-tubesheet joints for leaks. We only perform it when the customer requires in their specification. Usually it is for high purity processes that cannot handle any contamination, but we see it time to time in other services.
